The present invention relates to an apparatus for discharging predetermined amounts of liquid gas, preferably liquid nitrogen or other low-boiling point condensed inert gas, for the inertion and/or pressuring of containers, bottles, cans, or the like. The apparatus comprises a container which is connected through an inlet conduit to a source of condensed gas, is thermally insulated, and is disposed in a surrounding casing. The apparatus further includes means for maintaining a predetermined liquid level in the container and a dosage pump.
In the dosage of minor amounts of a low-boiling point, condensed gas the primary object is to supply the correct amount of gas to each container and to minimize or avoid losses of condensed gas; for example, the gas which falls outside the container when continuous flow is employed.
An apparatus for the dosage of liquid nitrogen is previously known in the art from DE-OS 27 32 318 in which a disc which is pivoted about a vertical axis is rotated beneath the outlet aperture for the nitrogen. Depending upon the configuration of the disc, the discharge aperture will be closed during a greater or lesser period of time.
It is further known from GB-A-2 091 228 to control the dosage of a low-boiling point, liquid gas by means of a needle valve which constitutes the outlet aperture of the dosage apparatus. In this prior art construction the valve needle is drawn upwardly by a solenoid so that liquid nitrogen may depart from the container of the dosage apparatus. This prior art apparatus suffers from the drawback that ice crystals may be formed at the valve seat during its operation, which may lead to irregular flow through the valve.